Utility knife



FIG. 1 is a perspective view of a utility knife showing my new design;

FIG. 2 is a front end view thereof;

FIG. 3 is a rear end view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is another perspective view of the utility knife with the blade being extended therefrom.

The broken lines illustrate portions of the design that form no part of the claimed design. 

The ornamental design for a utility knife, as shown. 